Arecibo Radar Astrometry of the Galilean Satellites from 1999 to 2016

Brozović, M.; Nolan, M. C.; Magri, C.; Folkner, W. M.; Jacobson, R. A.; Harcke, L. J.; McMichael, Joseph G.; Richardson, James E.; Harmon, J. K.; Taylor, Patrick A.; Benner, L. A. M.; Giorgini, Jon D.; Ostro, S. J.; Perillat, Philip; Hine, A. A.; Naidu, Shantanu P.; Slade, M. A.; Rożek, A.; Rodriguez-Ford, Linda A.; Zambrano-Marín, Luisa F.

doi:10.3847/1538-3881/ab7023

Cited by 8 publications

(3 citation statements)

References 36 publications

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“…The most precise measurements from Earth are obtained by mutual occultations of the satellites (which occur every 6 years), occultations of stars by the satellites (which are valuable but rare), and radar ranging. Radar ranging from Arecibo has obtained the most precise positional measurements on Io from Earth to date, with a precision of just over 5 km (Brozović et al 2020). Past research has found contradictory results for the magnitude and direction of Io's secular orbital evolution (e.g., Goldstein & Jacobs 1995, Aksnes & Franklin 2001.…”

Section: Orbital Evolution Of Iomentioning

confidence: 99%

A 2020 Observational Perspective of Io

Pater

Keane

Kleer

et al. 2021

Annu. Rev. Earth Planet. Sci.

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Jupiter's Galilean satellite Io is one of the most remarkable objects in our Solar System. The tidal heating Io undergoes through its orbital resonance with Europa and Ganymede has resulted in a body rich in active silicate volcanism. Over the past decades, Io has been observed from ground-based and Earth-orbiting telescopes and by several spacecraft. In this review we summarize the progress made toward our understanding of the physical and chemical processes related to Io and its environment since the Galileo era. Io science has been revolutionized by the use of adaptive optics techniques on large, 8- to 10-m telescopes. The resultant ever-increasing database, mapping the size, style, and spatial distribution of Io's diverse volcanoes, has improved our understanding of Io's interior structure, its likely composition, and the tidal heating process. Additionally, new observations of Io's atmosphere obtained with these large optical/infrared telescopes and the Atacama Large Millimeter/submillimeter Array reveal the presence of volcanic plumes, the (at times) near-collapse of Io's atmosphere during eclipse, and the interactions of plumes with the sublimation atmosphere. ▪ Extensive new data sets of Io at ultraviolet, mid- to near-infrared, and radio wavelengths have been gathered since the Galileo era. ▪ New data and models inform us about tidal heating, surface properties, and magma composition across Io—although key questions remain. ▪ Atmospheric observations indicate a dominant sublimation-supported component and reinforce the presence of stealth volcanism. ▪ Observations of volcanic plumes show high gas velocities (up to ∼1 km/s) and their effect on Io's atmosphere. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 49 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Section: Orbital Evolution Of Iomentioning

confidence: 99%

A 2020 Observational Perspective of Io

Pater

Keane

Kleer

et al. 2021

Annu. Rev. Earth Planet. Sci.

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“…The case of Galilean moons is a critical example because Jupiter's brightness in the Field of View (FoV) would quickly saturate the CCD, thus providing positions with uncertainties that range between 100 and 150 milliarcseconds (mas; Kiseleva et al 2008). This scenario motivates the search for alternative methods for the astrometry of these satellites, such as the mutual phenomena events (Aksnes & Franklin 1976;Aksnes et al 1984;Emelyanov 2009;Arlot et al 2014;Saquet et al 2018;Morgado et al 2019c, and references therein), mutual approximations (Morgado et al 2016(Morgado et al , 2019a, radar astrometry (Brozović et al 2020), and stellar occultations (Morgado et al 2019b), among others.…”

Section: Introductionmentioning

confidence: 99%

Milliarcsecond Astrometry for the Galilean Moons Using Stellar Occultations

Morgado

Gomes-Júnior

Braga-Ribas

et al. 2022

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A stellar occultation occurs when a Solar System object passes in front of a star for an observer. This technique allows the sizes and shapes of the occulting body to be determined with kilometer precision. In addition, this technique constrains the occulting body’s positions, albedos, densities, and so on. In the context of the Galilean moons, these events can provide their best ground-based astrometry, with uncertainties in the order of 1 mas (∼3 km at Jupiter’s distance during opposition). We organized campaigns and successfully observed a stellar occultation by Io (JI) in 2021, one by Ganymede (JIII) in 2020, and one by Europa (JII) in 2019, with stations in North and South America. We also re-analyzed two previously published events: one by Europa in 2016 and another by Ganymede in 2017. We then fit the known 3D shape of the occulting satellite and determine its center of figure. This resulted in astrometric positions with uncertainties in the milliarcsecond level. The positions obtained from these stellar occultations can be used together with dynamical models to ensure highly accurate orbits of the Galilean moons. These orbits can help when planning future space probes aiming at the Jovian system, such as JUICE by ESA and Europa Clipper by NASA. They also allow more efficient planning of flyby maneuvers.

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“…The case of Galilean moons is a critical example since Jupiter's brightness in the Field of View (FoV) would quickly saturate the CCD, thus providing positions with uncertainties that range between 100 and 150 milliarcseconds (mas) (Kiseleva et al 2008). This scenario motivates the search for alternative methods for the astrometry of these satellites, for example, the mutual phenomena events (Aksnes & Franklin 1976;Aksnes et al 1984;Emelyanov 2009;Arlot et al 2014;Saquet et al 2018;Morgado et al 2019c, and references therein), mutual approximations (Morgado et al 2016(Morgado et al , 2019a, radar astrometry (Brozović et al 2020), stellar occultations (Morgado et al 2019b), among others.…”

Section: Introductionmentioning

confidence: 99%

Milliarcsecond astrometry for the Galilean moons using stellar occultations

Morgado,

Gomes-Júnior,

Braga-Ribas

et al. 2022

Preprint

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A stellar occultation occurs when a Solar System object passes in front of a star for an observer. This technique allows the determination of sizes and shapes of the occulting body with kilometer precision. Also, this technique constrains the occulting body's positions, albedos, densities, etc. In the context of the Galilean moons, these events can provide their best ground-based astrometry, with uncertainties in the order of 1 mas (∼ 3 km at Jupiter's distance during opposition). We organized campaigns and successfully observed a stellar occultation by Io (JI) in 2021, one by Ganymede (JIII) in 2020, and one by Europa (JII) in 2019, with stations in North and South America. Also, we re-analyzed two previously published events, one by Europa in 2016 and another by Ganymede in 2017. Then, we fit the known 3D shape of the occulting satellite and determine its center of figure. That resulted in astrometric positions with uncertainties in the milliarcsecond level. The positions obtained from these stellar occultations can be used together with dynamical models to ensure highly accurate orbits of the Galilean moons. These orbits can help plan future space probes aiming at the Jovian system, such as JUICE by ESA and Europa Clipper by NASA, and allow more efficient planning of flyby maneuvers.

show abstract

Arecibo Radar Astrometry of the Galilean Satellites from 1999 to 2016

Cited by 8 publications

References 36 publications

A 2020 Observational Perspective of Io

A 2020 Observational Perspective of Io

Milliarcsecond Astrometry for the Galilean Moons Using Stellar Occultations

Milliarcsecond astrometry for the Galilean moons using stellar occultations

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